Posted on April 09, 2014
We are nearing the beginning of February, and gardeners everywhere are beginning to receive their first seed catalogs in the mail, scan the internet for new ideas and varieties, and prepare for planting day. While many of us have a wait until we can till up the garden soil and sow outdoors, we can still get a head start on planting by starting an indoor growing operation.
Starting from seed is a rewarding way to extend your growing season and expand the diversity of your garden beyond what is typically available for transplant at your local nursery. Retail seed racks, seed catalogs, and online seed companies offer seemingly endless possibilities for your garden—where your nursery or garden center may only have three or four varieties of tomato transplants, a catalog may have several pages of tomatoes in every size, shape, and color, including organics and heirlooms. Seed-starting is also a great way to give your plants a boost before they move outside. Indoors, you can ensure that the light, temperature, planting medium, and humidity are ideal for healthy happy growth, creating the highest quality transplant possible before frost danger is over and your outdoor gardening can begin. And if you are successful at germinating and growing from seed, your surplus transplants make wonderful gifts for the other gardeners in your life when springtime finally arrives (a benefit of seed-starting that we particularly enjoy).
To begin starting from seed, you will need a few basic pieces of equipment:
Seeds – Because it will be difficult to seed-start without any seeds.
Containers – Peat pots, Cow Pots, plastic pots, or DIY pots made of old egg cartons or newspaper—there are many options when it comes to planting containers for your seeds, and you’re sure to find supporters of each when you’re doing research. Choose a container that will give your young plants enough room to stretch their feet out.
Planting Tray and Cover – Moisture is incredibly important when starting from seed, and placing your containers in a simple tray with a lid will work wonders to trap humidity and keep your planting medium evenly moist without being soaked. The covered tray will also help to keep your little seeds warm and cozy and excited to germinate.
Planting Medium – To give your seeds the best chance at healthy germination and growth, use a special seed-starting planting mix in your containers. These mixes are often soil-less, containing a mixture of vermiculite, perlite, peat, coir, compost, and other organic matter or amendments. Seed-starting mixes are designed to provide excellent drainage and moisture retention. It is possible to create your own seed-starting mix from these ingredients, too, but be sure that you are not using garden soil in your mixture—it is generally advised that garden soil not be used for seed-starting as it is quick to become compacted and won’t provide the drainage necessary for your seeds.
Spray Bottle – Moisture is important to growing seeds, but it is just as important that you not drench them with water. The idea is to add just enough water to keep your planting mixture evenly moist without disturbing your seed. A mister or spray bottle is a great way apply water gently to the top of your soil and avoid overwatering or seed displacement that could occur from using a watering can. If your containers have good drainage holes in the bottom or absorb moisture well, you could add a small amount of water to the bottom of your planting tray so your planting mix can absorb moisture through the bottom of the pot. Watering from the bottom eliminates the need for a mister, and will not bother your seeds.
Grow Light – Providing adequate light for your plants once they’ve germinated is critical. Plants without proper access to light grow tall and “leggy,” and are not the healthy transplants you’ll want for your garden. If you do not have a window that provides several hours of direct bright sunlight, you will most likely have to purchase a grow light to keep your seed-starts healthy. There are a lot of different grow light options available, but according to most, a fluorescent light is best when it comes to balancing effectiveness and affordability. Fluorescent grow lights are available in long tube or compact forms that offer intense full-spectrum light that mimics what the plant would receive outside. These special grow lights can be a little on the pricey side, but some gardeners claim to have had success with ordinary shop light fluorescent bulbs. Regardless of what type of light you use, be sure to keep your light close to your seedlings to prevent them from getting leggy, and leave your light on for 12 to 18 hours a day with a dark period in between (turn it on at breakfast, and off at bedtime).
Heated Mat – Seeds like to be warm and toasty during the day to germinate, but keeping the planting medium at an ideal temperature can be tricky if your home tends to be on the cooler side during the winter months. A germination mat will help you keep gentle heat on your seedlings—enough to encourage germination and growth, but not so much as to dry out the planting mix or bake your plants.
Equipment acquired? Good. Now, let’s figure out when to plant.
The first piece of information you need is the expected or predicted last frost date for your area. This date will be the measuring mark for all of your plantings this spring and summer. Find your expected last frost dates by using the many maps, calculators, and frost date charts on the internet or asking your local extension office. If the resource you are using offers you a range of dates, consider erring on the late side of those dates so as not to be affected by surprise late frosts. A tip here: if you are just beginning or are an experienced gardener and don’t keep a planting journal, you might want to give it a try. This is where writing things down, like past frost dates, planting dates, and observed weather, may help you in deciding when you should plant.
Once you have your last frost date, take a look at the seed packets you’ve purchased. Most of these packets will tell you exactly when to sow indoors and outdoors. If your packet says “sow indoors 4 weeks before last frost,” your planting date will be four weeks before your last frost date. Use your seed packet to determine when you should plant, but generally speaking:
Tomatoes 6-8 weeks before last frost
Peppers 6-10 weeks before last frost
Broccoli 6 weeks before last frost
Eggplant 8-10 weeks before last frost
Cabbage 5-8 weeks before last frost
You can also use the days to maturity or days until germination dates that appear on many seed packets to assist you in figuring out the best time to sow indoors and to transplant outdoors in your area.
When it is time to plant your seeds, put your seed-starting mix into a bucket and add just enough water to get your mix moistened throughout. Fill your chosen containers with this moistened mix and place them into your planting tray. Follow the directions on your seed packet to plant your seeds at the proper depth. If you aren’t sure how deep to plant your seeds, experts recommend that you sow seeds at a depth of one and a half to three times the diameter of the seed. Some seed packets may tell you whether or not your seed needs to germinate in the light or in the dark—if the former (coleus, columbine, snapdragon), your planting depth will be shallower, and if the latter, your seed will need to be completely covered. If you are planting tiny seeds, you may only need to sprinkle them on top of the mix and lightly brush them around with your fingers to cover them. Be sure to label your containers so you don’t forget what you’ve planted. Place the lid on your tray, your tray on your heating mat, and place it in a warm area. While you are waiting for germination, don’t neglect your seeds. Containers can dry out quickly, and you’ll want to make sure that your seed-starting mix stays moist.
When your seeds have germinated, you can remove the lid and place your tray under your light source. Continue to monitor your seedlings regularly to ensure that their soil is moist and that they are receiving enough light. If you are using a window light source, it would be wise to turn your tray every so often to expose all parts to the light. Once your seedlings form their first “true leaves,” (the leaves that come after those two little round ones) you can begin to fertilize your plants with diluted liquid fertilizer. If you have selected a non-soil-less mix or a mix with fertilizer already added, you will not need to add any other fertilizer.
As the time gets closer to transplanting outdoors, you will need to harden your plants off to get them used to the environment outside. Do this by taking your tray out on a mild day. Leave it outside for a couple of hours, and return it indoors. For the next week to two weeks, repeat this, but tack a couple more hours on each time so your transplants gradually spend more and more time outside.
On planting day, thoroughly water your transplants. Dig a hole for them that is a bit wider than their containers so that they have room to grow. If you have used peat, Cow, paper, or another material that can break down in the soil, you can plant your entire transplant, container and all, into the garden. If you have used plastic containers, gently slide the transplant from the container and plant. The transplants should be planted at the same level as the container. It is imperative that you water these newly transplanted seed-starts regularly.